1. Field of the Invention
The invention relates to a self-propelled construction machine for working roadways or surfaces, comprising a machine frame supported by a crawler track and a milling drum which can rotate about an axis of rotation extending transverse to the working direction of the construction machine and is arranged on the machine frame.
2. Description of the Prior Art
Self-propelled milling machines which have a milling drum equipped with milling tools are known for working on roadways. Since the milling tools are subjected to a high level of mechanical stress, it is necessary to sufficiently cool the tools. It is known to spray the milling tools with a coolant which is provided in a coolant reservoir.
For cooling the milling tools, the known milling machines have a nozzle assembly which comprises a plurality of nozzles arranged parallel to the axis of rotation of the milling drum. The nozzles each produce a fan jet which is oriented orthogonally or tangentially to the outer surface of the milling drum. Since the individual fan jets overlap in part, a common spray jet is produced which extends over the working width of the milling drum and is directed towards the outer surface of the drum.
The known cooling devices for milling tools have proven effective in practice. However, a disadvantage is the relatively high consumption of coolant, which either makes a sufficiently large coolant tank necessary or makes it necessary for the coolant tank to be refilled during a shift. However, the enlargement of the coolant tank results in an increase in the weight of the construction machine and in an increase in the outer dimensions, whilst the need to refill the coolant tank reduces the availability of the construction machine.
DE 102 13 017 A1 (U.S. Pat. No. 7,984,952) describes a milling machine comprising a cooling device which comprises a plurality of nozzles which are arranged along an axis extending parallel to the axis of rotation of the milling drum. In order to reduce the consumption of coolant, it is proposed that the quantity of coolant added be controlled depending on a value which is characteristic of the instantaneous output of the milling drum.
The problem addressed by the invention is that of providing a construction machine having a reduced consumption of coolant for cooling the milling tools of the milling drum, so that the dimensions of the coolant reservoir can be reduced and/or the availability of the construction machine can be increased. A further problem addressed by the invention is that of providing a method for reducing the consumption of coolant for cooling the milling tools of a milling drum of a construction machine.